For thin refill leads, pencils have been used wherein a mechanism for feeding and anchoring the leads in the writing position is actuated by a push-button projection out of the rear end of the housing. The actuation of a push-button is frequently found disagreeable and there exists a need to actuate the mechanism of the writing instrument in a simpler manner. It is consequently the aim of the invention to permit an actuation of the mechanism by relative rotation of mutually adjacent housing sections about the longitudinal axis of the housing.